The present invention relates generally to outboard motors, and more particularly to apparatus for mounting an outboard motor to a boat transom providing for both the vertical positioning and tilting of the outboard motor on a boat transom.
Obviously, boats and motors come in different physical sizes, weights and horsepower. Furthermore, boats and outboard motors are made by different manufacturers and, therefore, it is virtually impossible that any given outboard motor will mate with any given boat to provide optimum performance.
For example, for best operation at speed, the cavitation plate of the outboard motor should be at the surface of the water to prevent air from reaching the prop. The vertical positioning of the ourboard motor on the boat transom will determine the position of the cavitation plate. This positioning will, of course, be different with different boat and motor combinations.
Further, the tilt of the outboard motor relative to the boat transom also is important. For example, a negative trim or tilt positions the prop at such an angle to generate a thrust vector in a direction to prevent the bow of the boat from raising up thus getting the boat on plane faster. In addition, a negative trim improves handling of the boat at low speeds in rougt water. A positive motor tilt or trim positions the prop at such an angle to generate a thrust vector more in align with the longitudinal axis of the boat at operating speed, thusly, providing a larger thrust vector component for propelling the boat in a forward direction. This tilt or trim positioning will be affected by the angle of the transom of the boat which varies from boat design and between boat manufactures.
It is also desirable that the outboard motor be positioned rearwardly enough of the boat transom to locate the prop beyond the disturbed water created by the boat hull trailing the transom as the boat moves through the water.
Various devices for adjustably positioning the outboard motor on the boat transom and other devices for adjustably tilting the outboard motor on the boat transom are known to the art. Examples of such devices are shown in U.S. Pat. Nos. 2,928,631 issued to C. G. Hartman; 4,099,479 issued to Tetsuya Arimitsv; 4,402,675 issused to Charles H. Eichinger; 4,406,634 issued to Clarence E. Blanchard; and 4,482,330 issued to Greg Cook.